Great question! The tongue should be a dark pinky colour naturally and it is this colour as it has a good blood supply to it. As the tongue has a good blood supply to it it also means that if it gets damaged it can repair itself very quickly. The tongue can change colour and this can be a sign of an infection or illness of some description. Sometimes if we have a rally bad cold and sore throat we get a furry coating on the tongue and this is the infection in the throat sticking to the tongue!